WoL ranking are pretty innaccurate, as most of the top ones are under very special circumstances (i.e. getting a bajillion Innervates and Tides so you can do nothing but spam bubbles all fight long).
Also, your guildies sound like d-bags (no offense). Why are they getting mad at you when you're 3rd or 4th by a slim margin, when they could be getting mad at the Holy Pallies or Resto Sham who are way the hell behind? If they reply "well the Holy Pallies are tank healing" then say "hurr durr so am I", and if they retort than Resto Shamans are underpowered you should laugh at them. (Yes, Resto Shamans need some cooldowns but they are perfectly capable of performing well on the meters.)
That's not to say you don't have room for improvement, naturally. I see you using Flash Heal more than Penance, and hardly touching Greater Heal. Hurricane is a poor enchant for a healer (use Heartsong until you can afford Power Torrent), you need some trinkets with static Intellect (Jar and Mandala are both very weak for Disc unless you're desperately running OOM). You need the Int/max mana meta gem, and 50 int to bracers is way better than 65 haste.
The biggest thing I see is your spec. Borrowed Time is a baseline must-have, and Inspiration is similarly valuable if you ever have to help out with the tanks which, according to your post, is definitely the case. You could take points out of Train of Thought (only useful if you cast GHeal a lot, which you don't according to the logs), Strength of Soul (okay talent, but extremely useful for H Maloriak), Darkness (haste is okay but not do-or-die), or a point out of Empowered Healing (you seem to be mostly a raid healer, so this wouldn't be a bad choice). Or, you could just drop Atonement altogether to grab all the other stuff you want. I flip-flop between two PvE Disc specs quite often depending on the fights we're working on :-P